Clone: RFB4
Background: The epitope recognized by antibody RFB4 is a 135 kDa type I integral membrane protein expressed by human B-cells. Precursor B-cells are surface-CD22 negative, but cytoplasmic CD22 positive. Mature B-lymphocytes express CD22 also on their surface.The RFB4 antibody permits the identification and enumeration of human B-cells using flow cytometry. Results must be put within the context of other diagnostic tests as well as the clinical history of the patient by a certified professional before final interpretation. Analyses performed with this antibody should be paralleled by positive and negative controls. If unexpected results are obtained which cannot be attributed to differences in laboratory procedures, please contact us.
Purification Method: Purified by Chromatography
Specificity: The CD22 mAb (clone RFB4) recognizes surface CD22 expressed by mature peripheral B-cells and cytoplasmatic CD22 expressed by precursor B-cells. The sensitivity of RFB4 mAb is determined by staining well-defined blood samples from representative donors with serial-fold mAb dilutions to obtain a titration curve that allows relating the mAb concentration to the percentage of stained cells and geometric MFI (mean fluorescence intensity).For this purpose, a mAb-concentration range is selected to include both the saturation point (i.e. the mAb dilution expected to bind all epitopes on the target cell) and the detection threshold (i.e. the mAb dilution expected to represent the least amount of mAb needed to detect an identical percentage of cells). In practice, 50 µl of leukocytes containing 10^7 cells/ml are stained with 20 µl mAb of various dilutions to obtain a titration curve and to identify the saturation point and detection threshold. The final concentration of the product is then adjusted to be at least 3-fold above the detection threshold. In addition and to control lot-to-lot variation, the given lot is compared and adjusted to fluorescence standards with defined intensity.
Formulation: PBS pH 7.2, 1% BSA, 0.05% NaN3
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UniProt: P20273
Caution: For professional users only. This reagent contains sodium azide. To avoid the development of hazardous conditions, reagents containing azide should be diluted in running water prior to be discarded. Similar to the work with other biological products, proper handling procedures are recommended.